A bullaun is simply a boulder or slab of rock with one or more artificial cup-shaped depressions ground into its surface. The water that collects in these hollows has long been considered curative or spiritually significant, and the stones themselves are thought to date from the early medieval period, though many may be considerably older. They are common enough as a category, yet each one carries its own local weight of custom and association.

Aghagower itself has a long ecclesiastical history, and the presence of a bullaun stone there fits a broader pattern. The village is associated with Saint Patrick, and its early monastic foundation, with its round tower and ruined church, places it firmly within the landscape of early Irish Christianity. Bullaun stones are frequently found in exactly such settings, positioned near holy wells, church enclosures, or the ruins of early monasteries, suggesting they were integrated into the devotional life of these places rather than being merely incidental features of the landscape. Whether they predate the Christian communities that later adopted them, or were made within those communities, remains an open question that archaeologists have not fully resolved.